Intermittently-operated signaling device



Dec. 3, 1929. L. A. KlLLE 1,738,299

INTERMITTENTLY OPERATED SIGNALING DEVICE Filed Nov. 30, 1926 fi'q. Z.

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Patented Dec. 3.1929

UNITED STATES PATENT OFFICE A. KILLE, F BOONTON, NEW JERSEY, ASSIGNOR 'IO BELL TELEPHONE LAB ORATOBIES, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK INTERMITTENTLY-OPERATED SIGNALING DEVICE Application filed November 30, 1926." Serial No. 151,626.

An object of the invention is to intermittently operate a lamp or other signalingdevices.

A. further objectof the invention is to simplify the circuits for operating interinittent signaling devices.

In telephone systems and elsewhere, 1t 1s often desirable to intermittently operate a signaling device, such as a lamp toprovide a flashing signal. In such cases,- ithas heretofore been the practice to use rather com plicated arrangements of vibrating relays or the like.

A feature of this invention'is an intermittently operated circuit employing an electric discharge device and a relay having a winding connected in the space current circuit'thereof and a contact connected in the cathode heating circuit, so that the operation 5 of the relay will open the heating circuit, thus cooling the cathode and releasing the relay to again close the heating circuit and repeat tlie cycle of operations.

. In one embodiment the flashing of the dis- 39 charge device itself is used as a signal.

In the preferred embodiment a single 'discharge device and rela are employed for operating one or more ashing lamps. The

id of the discharge device is normally iased so that substantially no current will flow in the space current circuit. The operation of a switch will impress a positive potential upon the grid producing a flow of s ace current which operates the relay to c ose a circuit for lighting the lamp and to.

open the cathode heating circuit. The lamp will remain lighted during the period re-- quired for the cathode to cool sufliciently to reduce the space current to a point at which the relay will release, at which time the circuitthrough; the lamp is opened and the cathode heatlng circuit is closed, causing the cathode to again heat up to' produce space current'to operate the relay thus repeating the. flashing cycle so long as the switch re-- mains operated.

Th's invention can be more readily understood by'reference to the following detailed description in connection with the drawing in which Fig. 1 shows a circuit employing an electric discharge device and relay for oper ating a pluralityof signaling lamps, and Fig. 2 shows a special type of switchboard lamp and circuit for intermittently operating it.

Referring to Fig. 1 there is shown a plurality of signaling lamps 5 arranged to be operated by a single flashing circuit." Associated with each of the lamps is a switch or key 4. The flashing circuit employs an electric discharge device 6. In the plate cir: cuit of the device is connected the winding of a relay 7 The back contact 8 of the relay is connected in circuit with a heating battery 9 and the cathode of the-device 6. The front contact 10 of the relay is connected in circuit with the lamps and a battery 11 which supplies current for lighting them. Space current is supplied to the device from a battery 12. The grid of the discharge device 6 is connected to the resistance 13, battery 14, re-

sistance 15, battery 16 and battery 12 to the cathode. Battery 16 is of substantially the same voltage as the battery 12 to counteract its effect on the grid. The battery 14 is employed for biasing the grid to prevent space current from flowingwhen all the keys 1 are open. With some types of discharge devices,

this battery may not be necessary. Resistance 13 is preferably one-tenth to one megohm and resistance 17 of the order of 50,000 ohms. The circuit arrangement shown, particularly with regard to battery and ground connections, is best suited for telephone switchboard wiring, and of course, may be greatly simplified for other uses. i

ed, the grid of the device being biased so that the space current is insuflicient to operate the relay7. Vhen a key 4 is closed, the grid' of the tube is brought to a positive potential with respect to the cathode by means of the battery 12 since the resistance 15 is high compared with the resistance of the lamp 5. This causes a space current to flow operating relay 7. The operation of the relay lights the lamp 5 by supplying current from battery 11 through front contact 10, lamp 5 and key 4. The operation of the relay also opens the back contact 8 opening the cathode heating circuit. ficiently to reduce the space current to a point at which the relay 7 releases, the lamp is extinguished by the breaking of contact 10 and the cathode heating circuit is again closed. This cycle repeats'itself, flashing the lamp as long as the key 4 remains closed. If both keys 4 are closed both lanips will flash. Any number of lamps may thus be flashed by a single flashing circuit, the number being limited only by the current carrying capacity of the relay contact 10. When all of the keys 4 are opened, the grid of the device again assumes a negative potential through resistances 15- and 13, reducing the space current sufliciently to release the relay 7.

It will be noted that when a key 4 is closed the low impedance lamp 5 is connected in shunt to the high resistance 15 and battery 16 thus eflectively short-circuiting'battery 16 so far as the polarization of the grid is concerned. This enables battery 12 to overcome the opposing polarizing battery 14 and to render the grid highly positive with respect to the cathode. As soon, however, as relay 7 operates, closing its armature contact 10, current from the battery 11, flowing through the low resistance lamp 5 to ground, increases the potential difference across the terminals of the lamp 5. This potential difference operates as a counter E. to the battery 12 in the grid polarizing ath including resistance 13, battery 14 and amp 5. This action re duces somewhat the positive potential of the grid with respect to the cathode.

The speed of flashing is determined by the characteristics of the cathode and may be controlled by regulating those characteristics, much more'accurate control being possible than with vibrating relays.

Fig. 2 shows a circuit employing a special type of lamp. This lamp 20 has a thermionically active filament 21 and an anode 22 surrounding the filament. This anode is made cylindrical in shape so as not to interfere with the end luminosity of the filament. A relay 23 is employed for producing flashing. The winding of the relay is'connected from the anode 22 through key 24 and battery 25 to the filament 21. The battery 26 When the cathode has cooled suf is closed space current flows from the battery 25 through the winding of the relay, actuating it and opening the contact 28 which opens the filament heating circuit. When the filament has cooled so as to reduce the space current suificiently to release the relay 23 the filament heating circuit is again closed to relight the lamp and repeat the flashing operation. The lamp cannot flash too rapidly for proper illumination since its flashing speed is largely regulated by the time characteristic of its own filamen What is claimed is:

1. The combination with a relay of means to cause said relay to operate intermittently, said means comprising an electricdispharge device having a thermionic cathode, a control electrode, a circuit controlled by said relay for varying the thermionic activity of said cathode and a second circuit controlled by said relay for varying the electrostatic condition of said control electrode.

2. An intermittently operated circuit comprisino a space discharge device having a cuit whereby the operation of the relay by the space current of the device opens the cathode heating circuit and the release of the relay closes the cathode heating circuit and a circuit controlled by said relay for varying the electrostatic condition of said control electrode.

3. An intermittently operated circuit comprising an electric discharge device having a thermionic cathode, an anode and a control electrode, a cathode heating circuit therefor, a relay having a winding connected in circuit with said anode and cathode'and a contact connected in said cathode heating circuit, means for normally biasing said control electrode to prevent the flow of space current suflicient to operate said relay, means for impressing a potential on said electrode to produce suflicient space current to operate said relay and means controlled by said relay for varying the bias of said control electrode.

4. The combination with an electron discharge device having a cathode, an anode, an impedance controlv element, an input circuit and an output circuit, of a source of potential common to said circuits, a second source of potential in said input circuit for balancing the effect of said. first mentioned source of potential upon said impedance control element and means for disturbing said balanc 5. The combination with an electron discharge device having a cathode, an anode,

an impedance control element, an input circuit and an output 'circuit, of a source of potential common to said circuits, a second source of potential in saidvin ut circuit for balancing the effect of said rst mentioned source of potential upon said impedancecontrol element, and a circuit control element for disturbing said balanced condition.

6. The combination with an electron discharge device having a cathode, an anode and an impedance control element, of a circuit connecting said cathode and anode, a source of potential in said circuit for producing a space discharge between said cathode and anode, a circuit connection extending from said control element to a point in said 1 first circuit between said source and said anode, in said circuit connection, including a second source of potential of substantially said circuit connection including a second source of potential of substantially equal value as in said first source but connected in an opposite direction and a third source of potential connected in such a direction as to 1m ress a negative polarity on said con- LINDLEY A. -KILLE.

equal value as said first source-but connected in an opposite direction and means for'varying the effective potential of said second source.

7. The combination with an electron discharge device having a cathode, an anode,

and an impedance control element, an input c1rcu1t, an output circuit and'a heating cir- .cuit for said cathode, of a source of potential,

and a relay in said output circuit for intermittently varying the heating current apcircuit-is at its minimum value.

8. The combination'with an electron discharge device having a cathode, an anode, and an impedance control element, an output circuit connecting said cathode and anode, an input circuit connecting said filament and said impedance control element, and a heatcircuit for said cathode, of means in sa1d output circuit forsimultaneously afiecting the electrical condition of said inputcircuit and said heating current circuit.

9. The combination with an electron discharge'device having a cathode, an anode and an impedance control element, an input circuit and an output circuit, a source of bias potential for said control element in said input circuit, a second source of potential common to said circuits, a third source of potential in said input circuit for balancing the effect of said second mentioned source of potential upon said impedance control element, and a circuit control element for disturbing said balanced condition.

10. The combination with an electron discharge device having a cathode, an anode and an impedance control element, a circuit connectin said cathode and anode, a source of potent1al in said circuit for producing a space discharge between said cathode and anode, a circuit connection extendin from said control element to a point in said first circuit between said source and said anode, 

